[net/predictor] Remove unsafe usage of WeakPtrFactory

chrome/browser/net/predictor.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/net/predictor.h"
 
 #include <algorithm>
 #include <cmath>
 #include <iterator>
 #include <set>
@@ skipping 294 matching lines @@
   }
 
   if (urls.empty())
     urls.push_back(GURL("http://www.google.com:80"));
 
   return urls;
 }
 
 void Predictor::DiscardAllResultsAndClearPrefsOnUIThread() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
-                          base::Bind(&Predictor::DiscardAllResults,
-                                     io_weak_factory_->GetWeakPtr()));
+  // The post task here is guaranteed to execute before the post task in
+  // ShutdownOnUIThread, because we must have a valid profile here. Note that

[mmenke, 2016/12/09 22:01:18]

nit:  --we

+  // the ChromeNetBenchmarkingMessageFilter calls unsafely (an existing bug)
+  // into the profile, but doing so would crash before this point anyways.
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&Predictor::DiscardAllResults, base::Unretained(this)));
   ClearPrefsOnUIThread();
 }
 
 void Predictor::ClearPrefsOnUIThread() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   user_prefs_->ClearPref(prefs::kDnsPrefetchingStartupList);
   user_prefs_->ClearPref(prefs::kDnsPrefetchingHostReferralList);
 }
 
 void Predictor::set_max_queueing_delay(int max_queueing_delay_ms) {
@@ skipping 353 matching lines @@
     return;
 
   std::unique_ptr<base::ListValue> startup_list(new base::ListValue);
   std::unique_ptr<base::ListValue> referral_list(new base::ListValue);
 
   // Get raw pointers to pass to the first task. Ownership of the unique_ptrs
   // will be passed to the reply task.
   base::ListValue* startup_list_raw = startup_list.get();
   base::ListValue* referral_list_raw = referral_list.get();
 
+  // The first post task here is guaranteed to execute before the post task in
+  // ShutdownOnUIThread, because we have a valid profile here.

[mmenke, 2016/12/09 22:01:18]

nit: --we

   BrowserThread::PostTaskAndReply(
       BrowserThread::IO, FROM_HERE,
-      base::Bind(&Predictor::WriteDnsPrefetchState,
-                 io_weak_factory_->GetWeakPtr(), startup_list_raw,
-                 referral_list_raw),
+      base::Bind(&Predictor::WriteDnsPrefetchState, base::Unretained(this),
+                 startup_list_raw, referral_list_raw),
       base::Bind(&Predictor::UpdatePrefsOnUIThread,
                  ui_weak_factory_->GetWeakPtr(),
                  base::Passed(std::move(startup_list)),
                  base::Passed(std::move(referral_list))));
 }
 
 void Predictor::UpdatePrefsOnUIThread(
     std::unique_ptr<base::ListValue> startup_list,
     std::unique_ptr<base::ListValue> referral_list) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
@@ skipping 490 matching lines @@
 }
 
 void SimplePredictor::ShutdownOnUIThread() {
   SetShutdown(true);
 }
 
 bool SimplePredictor::CanPrefetchAndPrerender() const { return true; }
 bool SimplePredictor::CanPreresolveAndPreconnect() const { return true; }
 
 }  // namespace chrome_browser_net